Error message

  • Warning: Undefined property: stdClass::$uri in theme_file_link() (line 801 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$uri in theme_file_link() (line 821 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in drupal_basename() (line 2485 of /var/www/html/mathtube.org/includes/file.inc).
  • Warning: Undefined property: stdClass::$filemime in theme_file_icon() (line 867 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_path() (line 911 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: strtr(): Passing null to parameter #1 ($string) of type string is deprecated in file_icon_path() (line 911 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_map() (line 954 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in theme_file_link() (line 833 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filesize in theme_file_link() (line 833 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filename in theme_file_link() (line 839 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$uri in theme_file_link() (line 801 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$uri in theme_file_link() (line 821 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in drupal_basename() (line 2485 of /var/www/html/mathtube.org/includes/file.inc).
  • Warning: Undefined property: stdClass::$filemime in theme_file_icon() (line 867 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_path() (line 911 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: strtr(): Passing null to parameter #1 ($string) of type string is deprecated in file_icon_path() (line 911 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_map() (line 954 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in file_icon_path() (line 926 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filemime in theme_file_link() (line 833 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filesize in theme_file_link() (line 833 of /var/www/html/mathtube.org/modules/file/file.module).
  • Warning: Undefined property: stdClass::$filename in theme_file_link() (line 839 of /var/www/html/mathtube.org/modules/file/file.module).
  • Deprecated function: Optional parameter $js declared before required parameter $element is implicitly treated as a required parameter in include_once() (line 1445 of /var/www/html/mathtube.org/includes/bootstrap.inc).
  • Deprecated function: Optional parameter $input declared before required parameter $form_state is implicitly treated as a required parameter in include_once() (line 1445 of /var/www/html/mathtube.org/includes/bootstrap.inc).

Sparse - Dense Phenomena

Speaker: Jaroslav Nesetril

Date: Fri, Feb 28, 2014

Location: PIMS, University of British Columbia

Conference: PIMS/UBC Distinguished Colloquium

Subject: Mathematics, Combinatorics, Computer Science

Class: Scientific

Abstract:

The dichotomy between sparse and dense structures is one of the profound, yet fuzzy, features of contemporary mathematics and computer science. We present a framework for this phenomenon, which equivalently defines sparsity and density of structures in many different yet equivalent forms, including effective decomposition properties. This has several applications to model theory, algorithm design and, more recently, to structural limits.